Hauv ntau cov haujlwm tsim khoom lag luam, xws li electroplating thiab photovoltaics, ntau cov dej khib nyiab nplua nuj nyob hauv nitrate yog tsim. Cov txheej txheem ib txwm siv rau kev kho cov dej khib nyiab nitrate, xws li evaporation crystallization thiab kev kho cov av pov tseg, feem ntau muaj qhov tsis zoo xws li kev siv hluav taws xob siab, kev ua haujlwm tsis zoo, thiab kev cuam tshuam rau cov pa phem thib ob.
Nyob rau tib lub sijhawm, lub ntiaj teb kev thov rau ammonia yog tas li nce. Raws li cov chiv, tshuaj raw khoom, thiab lub zog thauj khoom, ammonia plays lub luag haujlwm tseem ceeb hauv kev ua liaj ua teb thiab kev lag luam.
Nyob rau hauv cov ntsiab lus no, nws yog ib qho tseem ceeb heev thiab ceev nrooj los txhim kho cov cuab yeej siv tau zoo uas tuaj yeem kho cov dej khib nyiab nitrate kom zoo thiab rov qab tau ammonia.
Kev tshawb fawb tau tshwm sim ntawm "rov qab ammonia los ntawm nitrate nplua nuj dej khib nyiab siv lub membrane tsis muaj electrochemical system" tau luam tawm hauv Nature Sustainability.
Kev Tsim Kho Tshiab thiab Txoj Cai ntawm Membrane Free Electrochemical System
Txoj kev tshawb no nthuav tawm cov txheej txheem tshiab tsis muaj hluav taws xob tsis muaj hluav taws xob zoo (ECSN), uas muab txoj hauv kev tshiab thiab txoj hauv kev los daws cov teeb meem ntawm nitrate cov dej khib nyiab thiab rov ua kom ammonia.
Lub kaw lus cleverly integrates lub electrocatalytic txo cov nitrate (ENRR) technology rau hauv nws, ua tiav kev hloov dua siab tshiab ntawm nitrate nyob rau hauv cov dej khib nyiab rau high-purity ammonium chloride los ntawm tej electrode tshua thiab txheej txheem tsim, thiab ua kom tiav synchronous nitrate txo thiab ammonia rov qab.
Ib qho ntawm cov khoom tseem ceeb ntawm lub cev yog tooj liab npib tsib xee (MPCN) ua haujlwm electrode dai kom zoo nkauj nrog cov iav hlau npaj siv 3D tshuab luam ntawv. Cov txheej txheem kev npaj electrode no tshwj xeeb, siv cov txheej txheem laser melting los tsim cov txheej txheem electrode los ntawm txheej.
Nws muaj cov yam ntxwv zoo hauv ntau yam. Los ntawm cov qauv kev xav, nws tuaj yeem raug xam los ntawm X-ray suav tomography rov tsim kho uas nws muaj qhov tsim nyog porosity thiab ua tib zoo tsim txoj hauv kev electrolyte, uas yog qhov tsim nyog rau kev thauj cov reactants thiab tag nrho cov kev hloov pauv.
Nyob rau hauv cov nqe lus ntawm cov khoom siv, X-ray diffraction qauv thiab Rietveld refinement tshwm sim qhia tau hais tias nws muaj ib tug zoo crystalline qauv, thaum high-resolution kis electron microscopy dluab qhia tau hais tias lub electrode core yog ib tug tooj liab nickel alloy qauv, nrog ib tug txheej ntawm amorphous metallic. iav npog qhov chaw.
Qhov tsim ntawm txheej amorphous no yog ze ze rau qhov kub thiab txias ntawm qhov chaw thiab cov cheeb tsam sab hauv thaum lub sij hawm 3D luam ntawv txheej txheem. Qhov qis qis qis rau ntawm qhov chaw txhawb kev tsim cov qauv amorphous, thiab cov txheej txheem amorphous no ua rau cov electrode nrog corrosion kuj zoo heev, ua rau nws ua haujlwm ruaj khov hauv cov dej khib nyiab.
Tsis tas li ntawd, ECSN system kuj koom ua ke nrog UV pab tshem tawm tsev. Chav tsev no ua lub luag haujlwm tseem ceeb hauv cov txheej txheem electrochemical. Nyob rau hauv cov txheej txheem electrochemical, ammonia yog nquag mus rau theem nrab oxidation cov tshuaj tiv thaiv ntawm lub anode, uas ua rau txo qis hauv ammonia rov qab tus nqi.
UV pab stripping unit tuaj yeem tiv thaiv oxidation ntawm ammonia ntawm anode. Los ntawm qhov kev txiav txim ntawm lub teeb hluav taws xob, cov tshuaj sib npaug thiab cov tshuaj tiv thaiv kinetics hauv cov tshuaj tiv thaiv kab mob tau hloov pauv, tso cai rau ammonia kom tau txais txiaj ntsig zoo dua los ntawm cov tshuaj tiv thaiv kab mob thiab rov zoo, yog li txhim kho cov ammonia rov ua haujlwm ntawm tag nrho cov kab ke.
Kev tsom xam ntawm Electrode Performance thiab Catalytic Mechanism
MPCN electrodes muaj kev ua tau zoo hauv cov txheej txheem tsis muaj electrochemical. Hauv cov txheej txheem electrocatalytic nitrate txo cov tshuaj tiv thaiv (ENRR), nws qhov kev ua tau zoo tau raug tshuaj xyuas los ntawm ntau txoj kev sim.
Fourier transform infrared spectroscopy (FTIR) kev sim ntawm cov peev txheej sib txawv tau pom tias MPCN electrode muaj peev xwm adsorption zoo rau NO ∝⁻ thiab tuaj yeem txhawb kev tsim cov khoom nruab nrab thaum lub sijhawm ua haujlwm.
Cov ntaub ntawv online sib txawv ntawm electrochemical mass spectrometry (DEMS) qhia meej txog tiam NO, NO ₂, thiab NH3 thaum lub sij hawm cov txheej txheem tshuaj tiv thaiv, thiab los ntawm cov ntaub ntawv no, cov txheej txheem tshuaj tiv thaiv thiab cov tshuaj hloov pauv txoj hauv kev tuaj yeem raug taug qab.
Kev tshawb fawb ntxiv tau qhia meej txog cov ncauj lus kom ntxaws cov kauj ruam los ntawm NO ∝⁻ mus rau NH ∝ los ntawm kev suav cov ENRR dawb zog txoj hauv kev, thiab txiav txim siab tias kev hloov ntawm NO rau NOH yog tus nqi tswj cov kauj ruam ntawm tag nrho cov tshuaj tiv thaiv. Qhov kev tshawb pom no muab lub hauv paus tseem ceeb theoretical rau kev ua kom zoo dua electrode kev ua tau zoo thiab cov kev mob tshwm sim yav tom ntej.
Raws li qhov xwm txheej ntawm {{0}}.5 V, NH3-nitrogen tiam tus nqi ntawm MPCN electrode yog siab li 0.94 mmol h ⁻¹ cm ⁻ ², thiab Faraday efficiency tshaj 93% . Cov ntaub ntawv no qhia tau hais tias muaj txiaj ntsig catalytic kev ua tau zoo ntawm MPCN electrode hauv ENRR cov tshuaj tiv thaiv, uas tuaj yeem hloov pauv nitrate rau hauv ammonia sai thiab yooj yim.
Ntxiv mus, MPCN electrodes muaj qhov zoo tshaj plaws electrochemical stability, muaj peev xwm ua haujlwm tsis tu ncua thiab ruaj khov rau ntau tshaj 1000 teev ntawm kev lag luam tam sim no ceev ntawm 200 mA cm ².
Qhov kev ntsuas kev ruaj ntseg ntev ntev no tau ua tiav hauv cov dej khib nyiab tiag tiag nitrate. Los ntawm kev sib piv nrog lwm cov electrodes xws li Cu ua npuas ncauj, Ni ua npuas ncauj, MFCN, thiab lwm yam., qhov kev ntsuam xyuas tau ua los ntawm cov duab kho qhov muag ua ntej thiab tom qab cov tshuaj tiv thaiv, Raman spectrum sib piv, nrog rau cov nqi ceev hloov tom qab adsorption NO ₂ ⁻, uas tau hais ntxiv txog qhov zoo tshaj thiab kev ntseeg siab ntawm MPCN electrode hauv qhov tseeb daim ntawv thov scenario.
Daim ntawv thov kev ua haujlwm ntawm qhov system hauv kev kho dej khib nyiab tiag tiag
ECSN system tau pom tias muaj peev xwm siv tau zoo thiab muaj txiaj ntsig zoo hauv kev kho cov dej khib nyiab electroplating. Hauv kev sim kho cov dej khib nyiab tiag tiag, lub kaw lus tau hloov pauv ntau dua 70% ntawm nitrate rau hauv high-purity ammonium chloride. Qhov kev ua tiav ntawm qhov tshwm sim no yog vim muaj kev sib koom ua ke ntawm ntau yam khoom hauv lub cev thiab ua tib zoo ua kom zoo dua cov tshuaj tiv thaiv.
Los ntawm qhov kev xav ntawm tag nrho cov qauv tsim, nws suav nrog kev sib koom ua ke ntawm MPCN thiab IrO ₂ - Ta ₂ O ₅ / Ti electrodes, tshwj xeeb tsim los ntawm electrolytic cell, thiab chav tsev rau ammonia stripping. Txoj kev tawm tsam sab ntawm ammonia hloov mus rau nitrogen thaum lub sij hawm cov txheej txheem tshuaj tiv thaiv yog ib qho tseem ceeb cuam tshuam rau ammonia rov qab tus nqi.
ECSN system ua haujlwm zoo tiv thaiv cov tshuaj tiv thaiv ammonia oxidation (AOR) los ntawm lub teeb hluav taws xob. Los ntawm cov ntaub ntawv sim, nws tuaj yeem pom tseeb tias muaj qhov sib txawv tseem ceeb hauv kev tshem tawm tag nrho cov organic carbon (TOC) thiab kev xaiv ntawm NO ∝⁻ rau NH3 hloov dua siab tshiab nyob rau hauv cov xwm txheej ntawm lub teeb hluav taws xob. Lub teeb hluav taws xob ua tau zoo txhim kho tus nqi rov qab ntawm NH3.
Nyob rau hauv cov dej ntws-los ntawm electrolytic cell, saib xyuas qhov muaj peev xwm hloov pauv ntawm IrO ₂ - Ta ₂ O ₅ / Ti anode dhau sij hawm tau qhia tias cov txheej txheem ammonia stripping tau zoo suppressed AOR, ua kom muaj txiaj ntsig zoo dua ntawm ammonia.
Piv nrog rau cov roj teeb tso rau hauv ib txwm siv, ECSN system kuj qhia tau qhov zoo ntawm NO ∝⁻ tshem tawm kev ua haujlwm zoo. Nws qhov tshwj xeeb ntws tawm thiab hluav taws xob tsim tsim, nrog rau kev sib koom ua ke ntawm ntau yam khoom, ua kom cov nitrate txo qis thiab hloov pauv sai thiab meej, txhim kho kev ua tau zoo thiab zoo ntawm kev kho cov dej khib nyiab, txo cov sij hawm kho thiab tus nqi, thiab muab kev kho kom zoo. muaj txiaj ntsig thiab ua tau zoo rau kev kho dej khib nyiab hauv kev tsim khoom tiag tiag.
Kev txheeb xyuas nyiaj txiag thiab ib puag ncig
Kev txheeb xyuas kev lag luam thiab kev lag luam nrog rau kev txheeb xyuas lub neej ntawm ECSN system qhia tias nws muaj qhov ua tau zoo thiab qhov zoo ntawm kev lag luam thiab ib puag ncig.
Raws li kev txheeb xyuas kev lag luam thiab kev lag luam, piv nrog EC SL txoj kev kho ib txwm muaj, ECSN system txo tus nqi kho NO ∝⁻ cov dej khib nyiab ib lub cubic meter. Qhov no feem ntau yog vim nws cov txheej txheem tshuaj tiv thaiv zoo, kev siv hluav taws xob qis dua, thiab cov qauv siv yooj yim.
Hais txog tus nqi ntawm cov khoom siv, txawm hais tias cov txheej txheem kev npaj ntawm MPCN electrodes rau 3D luam ntawv yog qhov nyuaj, nws cov kev ua tau zoo thiab kev ruaj ntseg mus ntev txo qhov zaus ntawm kev hloov electrode thiab cov nqi kho. Nyob rau hauv lub sij hawm ntev, nws txo cov khoom siv tag nrho cov nqi peev. Nyob rau hauv cov nqe lus ntawm kev khiav hauj lwm cov nqi, lub siab conversion tus nqi thiab kev xaiv ntawm lub system txo lub zog noj thiab siv cov tshuaj reagents, ntxiv txo cov nqi khiav hauj lwm.
Hauv kev ua haujlwm tiag tiag, qhov nce hauv ammonia rov qab tus nqi txo tus nqi ntawm kev kho ammonia tom qab thiab kev lag luam los ntawm kev poob ammonia.
Los ntawm qhov kev xav ntawm kev ntsuas lub neej (LCA), ECSN cov tshuab tau pom qhov zoo ntawm ntau yam kev cuam tshuam ib puag ncig. Nyob rau hauv cov nqe lus ntawm lub tsev xog paj emissions, piv rau ib txwm siv txoj kev kho mob, nws emissions raug txo kom tsawg. Qhov no yog vim hais tias lub kaw lus siv tsawg zog thaum lub sij hawm ua hauj lwm thiab zam lub tsev xog paj emissions tshwm sim los ntawm cov tshuaj tiv thaiv nyob rau hauv tej yam kev kho mob txheej txheem.
Nyob rau hauv cov nqe lus ntawm terrestrial thiab dej toxicity, qhov tseem ceeb txo tau raug soj ntsuam vim txo cov pa phem theem nrab thiab kev kho mob zoo thiab transformation ntawm teeb meem tshuaj. Piv txwv li, los ntawm kev hloov nitrate mus rau hauv ammonium chloride, cov tsub zuj zuj ntawm nitrate nyob rau hauv ib puag ncig thiab muaj kuab paug ntawm av thiab dej lub cev raug zam. Nyob rau tib lub sijhawm, ammonium chloride kuj tuaj yeem siv los ua cov khoom siv tshuaj muaj txiaj ntsig, ntxiv dag zog rau ib puag ncig cov txiaj ntsig ntawm tag nrho cov kab ke.
Los ntawm qhov kev xav ntawm cov khoom ntws ntawm NO ∝⁻ recycling thiab NH ∝ ntau lawm thoob ntiaj teb, ECSN system muaj qhov tseem ceeb daim ntawv thov muaj peev xwm nyob rau hauv lub ntiaj teb no nitrogen voj voog. Nws tuaj yeem hloov cov khoom pov tseg nitrate kom zoo rau hauv cov peev txheej muaj txiaj ntsig ammonia, txhawb kev rov ua dua ntawm cov khoom siv nitrogen, txo cov kev siv thiab kev vam khom ntawm cov khoom siv nitrogen tshiab, thiab ua lub luag haujlwm zoo hauv kev txhawb nqa kev txhim kho thoob ntiaj teb nitrogen.